TOOL FOR MAKING JOINTS OF CLINCH TYPE
A tool making joints of clinch type between two or several sheet formed members, which tool comprises two separate tool parts, a first tool-part with a punch and a second tool-part provided with a die which co-operate for producing said joint. The punch is arranged to be driven in a linear movement in the direction of the co-axial die provided with a die cavity at the bottom of which an anvil (3) is arranged. A spring element (5) having the general form of a cylindrical cage has a surface which has been provided with a number of slots to form a corresponding number of long elastic arms (11) partitioned around the circumference of the cage with their free ends at the upper edge of the cage. Said free end of each arm (11) is provided with a bent flange (12) arranged to bear laterally against a corresponding movable element (4) to transfer the spring force to said element, and said bent flange (12) is additionally arranged to grip around a heel portion (13) of the corresponding movable element (4) in order to block the die element for axial movement relative to the cage being fixed to the die body.
The present invention relates to a tool for making joints of the so called clinch type between two or several sheet formed members of metal or non-metal. More particularly the invention refers to a tool for making small or very small joints with diameters of the order of a few millimetres.
BACKGROUND ARTThe technique as such is well known in the art. A suitable tool comprises generally two separate tool parts which co-operate for producing said joint. A first tool part has the form of a punch which in a linear movement is driven in the direction of a co-axial second tool part in the form of a die with a die cavity at the bottom of which an anvil is arranged.
For making the joint the sheet formed members are positioned against the second tool part, the die, provided with movable die elements arranged sliding laterally on a support surface against the forces from a resilient element. The resilient element could be a ring made of an elastomer or a toroid formed metal spring surrounding the movable die elements.
The approaching punch impacts on the surface of one of the members to be joined. The material of the two members is first drawn into the die cavity and subsequently due to the interaction between the punch and the anvil at the bottom of the cavity laterally extruded thereby displacing the movable die elements outwardly creating in the sheet formed members a mushroom formed button which interlocks the members.
A tool of this type is e.g. shown in the document U.S. Pat. No. 5,946,782, published as WO97/02912 on 30.01.1997, incorporated here by reference. FIG. 1 and FIG. 2 of that document show a tool for making joints between sheet-formed members 4, 5 comprising a first tool-part 1, 2, 3 with a punch 1 and a side pressing element 2 and a second tool-part 6, 11 provided with a support surface 9 from which an anvil 8 erects, a matrix 6′ comprising at least two matrix-parts 6 each having an upper active matrix surface 13 and being arranged around said anvil 8. Each matrix part comprises a portion 14 arranged sliding against said support surface 9 and being applied against the lateral surface of said anvil 8 by means of elastic means 7. Retention means 10 are arranged limiting the longitudinal movement of the matrix parts during the retraction of the punch 1. The upper active matrix surface 13, the portion 14 arranged sliding against said support surface 9 and said retention means 10 are arranged in that order from the top of the second tool-part 6, 11
The present invention is more particularly directed to such a second tool part in the form of a die with a die cavity at the bottom of which an anvil is arranged which second tool part is provided with a special type of resilient element.
The document EP12178068 shows a resilient or spring element which has the general form of a cage the surface of which has been provided with a number of slots having an acute angle, not necessary constant, relative the axis of the cage to form a corresponding number of long elastic arms or blades equally partitioned around the circumference. This resilient member produces the force against which the movable die elements are laterally displaced during the joining process. When the punch is retracted the movable die elements in contact with the deformed sheet members will be subjected to a vertical force trying to lift them up from their support surface. To prevent this, cooperating arrangements on the die elements and support elements on the die, parallel to the direction of the sliding movement of the die elements, have been provided. Thus, the resilient or spring element according to this document does not contribute to the retention of the movable die elements when the punch is retracted. As a consequence the cage formed spring element does not have to be fixed to the die body in the direction of the die axis.
BRIEF DESCRIPTION OF THE INVENTIONThe present invention has applications especially for producing joints of smaller dimensions but certain embodiments could also be used for larger dimensions. Joints of these dimensions find applications in e.g. watch industry, electronics and electrical industry as well as in automotive industry.
One of the objects of the present invention is to provide a second tool part which has laterally very small dimensions.
Another object of the invention is to provide a second tool part on which the spring element has the double function of providing the lateral resilient force during the formation of the joint as well as the vertical retaining function when the punch in the first tool part is retracted.
Another object of the invention is to provide a second tool part on which the spring element is easily mounted and if necessary replaced.
The present invention, which provides a solution to the said technical problems, is characterised according to the appended claims.
Other objects and advantages of this invention will be apparent from the reading of this description which proceeds with reference to the accompanying drawings forming part thereof and wherein:
The general form of the spring element can be more clearly seen in the
The free end of each blade 11 is provided with a bent flange 12 arranged to bear laterally against the movable element 4 to transfer the resilient force to said element and at the same time to grip around a heel portion 13 of the movable die element 4. Thus, if the cage 5 is then fixed to the die body 1 so that it is blocked for axial movement relative to this body for vertical forces transferred through the movable die elements emanating from the retraction of the deformed sheet members at the end of the joining procedure, then the die elements 4 will stay in contact with the support surface 10.
The fixing of the cage 5 to the die body 1 can be made in different ways. For small dimensions of the joints a particularly simple arrangement of the fixing is shown in
Another arrangement for the fixing is shown in
In
As at least one arm 11 is needed for each movable die element 4 the number of arms will be at least two. In the embodiments shown in the
A tool part as described above can thus be installed to co-operate with a suitable punch in e.g. a C-frame work head. Multiple tool arrays with these tool pairs are also possible. Typical die diameters could be 1.0 to 2.0 mm, and the tooling can be used for joining sheet metal thicknesses from e.g. 2×0.1 mm to 2×0.5 mm. Other dimensions of tooling according to the inventive idea are of course also possible.
Claims
1-10. (canceled)
11. A tool making joints of clinch type between two or several sheet formed members, which tool comprises two separate tool parts, a first tool-part with a punch and a second tool-part provided with a die which co-operate for producing said joint, the punch is arranged to be driven in a linear movement in the direction of the co-axial die provided with a die cavity at the bottom of which an anvil is arranged, the die is further provided with a die body and movable die elements arranged sliding laterally on a support surface arranged at an end portion of the die body perpendicular to the length axis of the die body against the forces from a spring element, said die comprises at least two movable die elements, wherein said spring element has the general form of a cylindrical cage the surface of which has been provided with a number of slots to form a corresponding number of long elastic arms partitioned around the circumference of the cage with their free ends at the upper edge of the cage, the free end of each arm is provided with a bent flange arranged to bear laterally against a corresponding movable element to transfer the spring force to said element, said bent flange is additionally arranged to grip around a heel portion of the corresponding movable element in order to block the die element for axial movement relative to the cage being fixed to the die body.
12. The tool according to claim 10, wherein the number of slots partitioned around the circumference is greater than or equal to the number of movable die elements.
13. The tool according to claim 10, wherein the cylindrical cage has an inner diameter which is essentially equal to the outer diameter of the die body.
14. The tool according to claim 10, wherein the cylindrical cage is fixed to the die body by means of an intermediate O-ring located in a circular groove on the die body being compressed between the cage and the die body.
15. The tool according to claim 10, wherein the cylindrical cage is fixed to the die body by means of one or several tongues located in the side wall of the cage fitting into a groove or separate holes in the body.
16. The tool according to claim 10, wherein the cylindrical cage is fixed to the die body by means of one or several screws or pins.
17. The tool according to claim 10, wherein the slots are rectilinear.
18. The tool according to claim 10, wherein the slots are parallel to the longitudinal axis of the die body.
19. The tool according to claim 10, wherein the slots are equally partitioned along the circumference of the die body.
20. The tool according to claim 10, wherein the slots are arranged with an angle relative to the longitudinal axis of the die body.
Type: Application
Filed: Nov 4, 2014
Publication Date: Aug 18, 2016
Patent Grant number: 10279387
Inventors: Olivier Dubugnon (Vullierens), Jean-Claude Faivre (Renens), Lars E. Johansson (Hagfors)
Application Number: 15/033,673